#include<iostream>
using namespace std;
int main(){
  int n,i;
  cin>>n;
  double sum=1,a[n+1]={1};
  for(i=1;i<=n;i++){
    a[i]=a[i-1]/i;
    sum+=a[i];
  }
  cout.precision(10);
  cout<<fixed;
  cout<<sum;
}